                           (merge tree
                                  (morph-walk-tree tree))))
      :language "en"
+     :lookup (fn [arg]
+               (analyze arg lexicon))
      :morph fo
      :grammar grammar
      :lexicon lexicon

     :language "en"
     :morph fo
     :grammar grammar

     ;; Will throw exception if more than 1 rule has the same :rule value:
     :grammar-map (zipmap

                        (do
                          (merge tree
                                 (morph-walk-tree tree))))
     :lookup (fn [arg]
               (analyze arg lexicon))
     :grammar grammar
     :morph fo
     :lexicon lexicon
